Pressure-equalizing brake-applying device



May 29, 1923. 1,457,156

0. J. FROCK PRESSURE EQUALIZING BRAKE APPLYING DEVICE Filed May 12, 1922 awvemtoz 5554/; J. fims'rr Patented Maize, 1923.

UNITED STATES OSCAR J. EROCK, OI WILMINGTON, DELAWARE PRESSURE-EQUALIZING BRAKE-APPLYING- nnvrca. v

--App1ication filed May 12, 1922. Serial No. 560,429.

To all'wlzom it may concern:

Be it known .that I, Oscar: J. citizen of the United States, residing at Wilmington, in the county of New Castle 5 and State of Delaware, have invented certain new and useful Improvements in Pressure-Equalizing Brake-Applying Devices, of which the following is a specification.

This invention relates to a brake applying device and has special reference to a device for operating brakes of the hydraulic type and placing the fluid under pressure,

One object of the invention is to rovide brake applying means having a p urality of cylinders connected with the brakes and common operating means for the pistons of the cylinders so constructed that pressure F ROCK, a

applied can be equalized and the brakes' properl applied.

Anot 1er object of the invention is to so construct the cylinders and pistons that if a pipe leading from one of the cylinders to a brake should be punctured, the outlet of the cylinder may be closed by the piston and operation of the second cylinder continued.

Another object of the invention is to so construct the brake applying means that the pistons may be operated at equal pressure 30 from a common operating pedal through the medium of toggle links extending from the pedal, the cylinders being pivotally mounted so that they swing towards eaci other when pressure is applied to the pedal.

Another object of the invention is to provide an improved arrangement of valves for the cylinders so that fluid may be sucked into the cylinders to replace fluid which may escape and so that if excessive pressure is applied, a portion of the fluid in the cylinders may be permitted to escape into an auxiliary chamber.

Another object of the invention is to provide an improved arrangement of relatively large and small cylinders whereby the rear set of brakes may be applied at a greater force than the front set and the automobile stopped in a very eflicient manner and skiddin of the frontwheels prevented.

5o 'fiiis invention is illustrated in the accompanying drawings wherein:

Figure 1 is a diagrammatic view showing the improved brake applying means in an inoperative position. a

Figure 2 1s a similar view showing the brake applying means in the operative po- Figure 5 1s a' fragmentary transverse sec-' tional view of valves.

This improved brake appl ing device is for use in operating hydrau ic brakes and is so constructed that the front and rear brakes may be applied at the same time by a common operating element. The treadle 1 is pivotally mounted where it can be readily reached by the. operator of the car. plunger 2 is pivotally connected with the treadle intermediate its length and has its lower end pivotally connected to the iston rods 3 which extend into the cylin ers 4 and carry pistons 5. The cylinders 4 are pivotally mounted in spaced relation to the chassis or to body and the showing a modified construction cylinders extend towards each other as shown. By comparing Fig; 1 with Fig. 2, it will be readily seen that when the treadle is moved downwardly the pistons are moved in diverging relation to each other and forced into the cylinders which will be swung downwardly and towards each other thereby causing the pistons to apply pressure to liquid or other fluid in the cyl inders and force this fluid through the pipes 6 to apply the brakes which will have a conventional construction. It will be any suitable part of the car readily seen that when the treadle is moved downwardly the two pistons will first be brought into engagement with the fluid. in the cylinders and furtherv pressure upon the treadle will causee'ual pressure to be set up in the two cylin ersand the front and rear brakes applied with equal force. In some machines, it is preferred to have the rear brakes applied with greater force than the front brakes and when this is desired the two cylinders will be of different sizes and the piston rods of different lengths. The cylinder having the pipe leading to the front brakes is of greater diameter than the cylinder for the rear brakes and the piston rod for the piston of the front cylinder is longer than the rear piston rod. Therefore, due to the relative proportions of the toggle linkage and the diameters of the two pistons llU when the treadle is moved downwardly, the pressure upon the brakes controlled by the rear cylinder is greater and the machine can be stopped without danger of the front wheels skiddin Reference will now be had to Fig. 4 where the cylinders and pistons are illustrated in detail. Each cylinder 4 is provided with a solid base 7 having an opening 8 formed therein through which a pivot pin or rod may pass and the base is further provided with a fluid passage 9 terminating in an enlarged and t ireaded socket 10 to receive the packing gland or nut 11 which serves to secure the pipe 6. The free end portion of the cylinder is closed by a removable cap or head 12 having a pocket 13 formed therein to receive the collar 14 which serves to limit outward movement of the piston rod 3 and also serves as an abutment to permit the cups 15 which form the piston head to be firmly held in place when the securing nut 16 is tightened. This nut 16 is provided with a reduced neck portion 17 so that the spring 18 which is in the lower portion of tie cylinder may have roper engagement with the nut and yielda ly hold the piston and piston rod against inward movement. The pistons will therefore be normally held in the inoperative position shown in Figs.

1, 3 and 4 but may be moved against the.

action of the springs to the operative pressure applying position shown in Fig. 2. The inner en portion of the fluid passage 9 is formed into a valve seat 19 and the free end of the piston rod is tapered to provide a valve end 20 so that in case the pipe leading to the front or rear brakes should break or leak, the end of the piston rod of the cylinder controlling this set of brakes can be moved into the valve seat 19 and when this movement has stopped the piston of the second cylinder then moved to apply pressure to the fluid therein and cause the second set of brakes to operate properly.

when the brakes are applied, a certain amount of the ,fluid is liable to leak out and therefore each cylinder has been provided with a pocket or chamber 21 in which a surplus supply of fluid may be kept. This chamber communicates with the cylinder through ports 22 and 23 formed in a thickened portion or shoulder 24 and valves 25 and 26 are provided to control passage of the fluid through the ports 22 and 23. The valve 25 opens into the chamber 21 and constitutes an escape or safety valve so that if too much pressure is applied to the treadle some of the fluid can pass from the cylinder into the chamber 21 and the valve 26 opens into the cylinder so that when pressure is a removed from the treadle and the springs return the pistons to-the normal position shown, fluid can be drawn from the chamber into the cylinder to replace any which may have leaked out or been forced past the valve 25. A removable cap 27 is provided so that access may be had to the valves 25 and 26 for assembling and repairing and.

In some cases, it is desired to have the 7 surplus fluid stored in a se arate container instead of having the cylinders provided with the chambers 21 and when this is the case, the structure shown in Fig. 5 will be made use of. In this figure, the cylinder has been shown provided with a single port 29 instead of the two ports 22 and 23, and the cylinder is provided with a collar 30 which is threaded and carries a block 31 in which is formed pockets 32 and 33. Oppositely opening spring closed valves 34 and 35 which correspond to the valves 25 and 26 are provided in the pockets to control the passage of fluid through the pockets and ports 36 and 37 which lead from the pockets to a common passage 38. A pipe or tube 39 is secured to the block 31 by means of a nut 40 and will be led to a suitable fluid container positioned at'any suitable place on the car.

In view of the fact that the block terminates in spaced relation to the bottom of the collar 30, it will be readily seen that the fluid can pass freely through the port 29 either into or out of the cylinder accordin to whether pressure is exerted to force the uid by the valve 34 or suction created in the cylinder to draw the fluid by the valve 35.

There has thus been provided a brake operating device which is so constructed that hydraulic brakes can be operated in a very efficient manner and the pro er amount of fluid kept in the cylinders an damage from excessive pressure prevented. There has further been provided an eflicient device for causing the proper pressure to be applied to the pistons and for permitting one set of brakes to be operated in case the other set should be rendered inoperative.

I claim:

1. In a hydraulic brake applying structure, cylinders pivotally mounted for swinging movement towards and away from each other, pistons in the cylinders having piston rods extending through the free ends of the cylinders in converging relation, and operating means including a plunger having one end pivotally connected with the outer ends of said piston rods for imparting movement to the rods and pistons and setting up brake applying pulsations in columns of fluid leading to fluid brakes.

2. The structure of claim 1 having one cylinder of greater diameter than the other cylinders each and havin its piston provided with a pie-- ton rod 0 greater length than the piston rod of the smaller cylinder whereb brakes havin fluid tubes/connected with t 0 small cylin er may be operated with greater force means yieldably holding the pistons against inward movement and serving to move the pistons and piston rods outwardly when pressureupon the pl er is removed.

5. The structure o glaim 1 having the piston rods extended beyond the inner ends of the pistons and terminating in valve ends, the cylinders each havin a fluid passage in its lower end provided at its inner end with a valve seat for receivingthe valve end of the iston rod and rimtting closing of the uid passage at its inner end.

6.-The structure of claim 1 having each cylinder provided with a side chamber constituting a reserve reservoir for fluid, the cylinder having its walls provided with ports communicatin with the reserve reservoir, and check va ves for said ports, one valve opening into the reservoir and constituting an escape valve and the other valve being ogened by suction in the cylinder to permit uid to be drawn into the cylinder from the reservoir.

7. The structure of claim 1 having the provided with a side, chamuld and side ports for comthe chambers, the chamber her for reserve mumcatmg with being provided with a filling port and a closure for said filling port, and inwardl trollin passage of fluid through the side P s rom the cylinder into the side chamexcessive piston rods is actuatedspaced cylinders be; and from the side chamber into the cyl- In 01'- 8. The structure of claim 1 having the glinders provided with side ports andeck valves for controlling passage of fluid through the side ports whereby fluid under pressure may escape from the cylinder and suction in the cylinder cause fluid to be drawn into the cylinder.

9. In a fluid brake applying structure,

spaced cylinders, pistons in the cylinders having piston rods extending from the cylinders and towards each other, and an ac tuating plunger between said cylinders and connected with the piston rods for imparting movement to the same and setting up brake applying ulsations in columns of fluid leading to uid brakes.

10. In a fluid brake applying structure, positioned in converging relation, pistons in said cylinders having piston rods extending from the cylinders and actuating means connected with the piston rods for imparting movement to the same and settin up brake applyin ulsations in columri of fluid leading %o fluid brakes.

11. The structure of claim 10 having the cylinders of different diameters to cause brakes controlled thereby to be applied at different presures. Y

12. The st-ructure of laim 10 having the piston rods of different lengths to cause dif-,

ferent leverages to be exerted when the actuating means is moved in an operative direction. v v

, 13. In a fluid brake applying structure, separate cylinders adapted for operative connection with fluid pressure brakes, one cylinder being adapted to supply greater pressure than the other, pistons in said cylmders having piston rods extending from the same, and means associated with said piston rods for imparting movementto the same and causin ressure in the c linders. and outwardly opening check valves con g p OSCAR VJ. FROOK. 

